In 1903 W. C. Handy was waiting for a train in Mississippi when saw and heard "A lean loose-jointed Negro...plunking a guitar beside me while I slept... As he played, he pressed a knife on the strings of the guitar in a manner popularized by Hawaiian guitarists who used steel bars....The singer repeated the line three times, accompanying himself on the guitar with the weirdest music I had ever heard." So he wrote in his autobiography "William Christian Handy, Father of the Blues"
What Handy heard was the blues. But even in 1903, with the popular format of the 78 rpm record decades away, Handy knew enough to call the slide guitar sound "Hawaiian." It was the distinctive notes which don't exist on the European scale he heard...the sound of notes in between frets created by the slide. The sound Tom Dowd couldn't believe when he paired Duane Allman with Eric Clapton to create Layla. The sound Mick Taylor added to the best Rolling Stones recordings. The sound lap steel preachers in Florida use to scream.
Go figure. The unearthly sound of Charlie Patton, generally credited with being the first "Delta Bluesman" and a great influence on all who followed (including Robert Johnson) didn't make his first recordings until 1929, over 25 years later, though he was offered a job playing in Handy's band in 1916. Patton played slide so well he often finished his phrases with strings instead of enunciating them verbally. But Charley had never been to Hawaii. So did the blues originate on a Pineapple plantation rather than in a Cotton field?
For that matter, when did Bob Dunn, astounding lap steel slide guitarist for Milton Brown's Western Swing Band visit Hawaii? Dunn played the first electric lap slide guitar with Brown in 1935 and the same sound became prominent in Country as well as blues. Ever hear old Hank without weeping steel frills and fills?
The answer probably lies with Joseph Kekuku. He created the slide guitar sound in 1885 while walking along a road in Hawaii. He hadn't been to the Mississippi Delta. It was some 40 years after that the National Guitar became prized among blues musicians like Tampa Red. Those resonator guitars became popular because they could produce that slide sound and could be heard over the noise of rent parties, speakeasies and bar fights.
Images from "5 Minute Hawaiian Guitar or Steel Guitar Illustrated (no date, circa 1925) Collection Jim Linderman